1. Field of the Invention
The present invention relates generally to semiconductors, and more particularly, to electronic interconnect structures having at least two different metals in a single metallization layer.
2. Background of Invention
Scaling down of active device dimensions in the manufacture of integrated circuits (IC) has improved circuit performance and increased the complexity and capability of the active devices packed on a semiconductor substrate. The high density ICs run at a higher and higher temperature. High temperature increases the likelihood of electromigration (EM) failure of interconnect structures within the IC.
In multi-finger applications in which the layout of the devices is such that the metal lines may be arranged in parallel stripes or fingers, these fingers may carry significant current densities and current limiting mechanisms, including electromigration, are a major concern. Such devices include: power amplifiers, RF switches, I/O drivers, small analog devices operating near peak ft, devices with moderate current densities but operating at high ambient temperature (above 80° C.) or chips that develop a large amount of heat during operation, and any device with long fingers.
Accordingly, an interconnect structure which is resistant to EM despite high operating temperatures is needed.